1. Field of the Invention
The present invention relates to a modular-type wiper device mounted on cars, buses, trucks or the like.
2. Description of the Related Art
Among wiper devices of this kind, there is a so-called modular-type wiper device into which components, such as a pair of right and left pivotal shafts, a wiper drive motor and wiper link mechanism, are integrated as a single modular unit. Today, such a modular type has been popularly employed because of the advantages as follows: compared to a type which is formed of components each of which is individually assembled into a vehicle's body, the modular type not only makes mounting operation easier because the modular unit into which all components are already integrated is assembled into the main body (frame), but also allows additional design reinforcement as needed, without design consideration to component-to-component intensity match to the main body side.
In such a prior art modular type, however, an entire bracket holding a wiper drive motor and a wiper link mechanism is made of a one-body construction of cast aluminum or cast zinc. Thus, the bracket itself is bulky and heavy. Furthermore, the die for forming the bracket is bulky and costly. It has been proposed, in an attempt to cope with this disadvantage, that the bracket itself be made compact and light weight by splitting it into two sections, a first bracket and a second bracket, the first bracket being connected to the second bracket by a frame member.
In most cases, to be suited to the configuration of the main body, a pair of right and left pivotal shafts of a wiper device is not arranged in a manner such that each shaft is parallel with the other shaft. When the first bracket is connected to the second bracket with the frame member to be one-body, the frame member is preferably of a linear structure, rather than a bent or twisted structure from the standpoint of manufacturing and mechanical strength. The frame member may be connected to each bracket using bolts or rivets. From the standpoint of assembly, it is required that the directions of insertion of bolts or the like be uniform. On the other hand, the brackets are formed of die cast using a die matched in reference to the axes of sleeves (the axes of the pivotal shafts) rotatably supporting the pivotal shafts. When connecting portions to be connected to the frame member are formed of die cast together with the sleeves, the axes of both sleeves are not aligned, and the mating surfaces of the connecting portions formed on the first and second brackets are not aligned in an attempt to connect both brackets with the frame member. Such an arrangement requires that a bent or twisted frame member be utilized, thereby making it impossible to keep the insertion directions of the bolts uniform. To ensure that the mating surfaces of the connecting portions are aligned in connecting the brackets, a complex combination of dies may be needed. Probably, special dies such as slide dies may be needed, requiring complicated and troublesome die control, presenting poor productivity, and consequently increasing the manufacturing cost.